A newly proposed classification for articulators-integrating virtual with conventional

Abstract

A new and simple articulator classification has been proposed which includes both mechanical and virtual articulators to meet with the modern day dental practice that has shown a gradual shift toward digital technology and workflow.

INTRODUCTION

Articulator is an analogue. either mechanical or digital, to which maxillary and mandibular casts may be attached to simulate some or all mandibular movements.[1] Articulator is an indispensable tool for the fabrication of dental prostheses that optimally function in patients’ mouth. The purpose of articulators is to simulate the range of jaw movements and serve as the starting point for the development and evaluation of occlusion.[2]

Articulators have significantly evolved, beginning from the 18^th century when the first primitive articulator was believed to be introduced by Phillip Pfaff,[3,4] to the most sophisticated instruments of present times that have a number of adjustable features. In fact, to keep pace with the current digital revolution and drift toward an all-digital workflow in dentistry, there has been a progression from mechanical articulators towards the development and usage of virtual articulators in the dental profession.[5,6]

With large numbers of articulators available in the market having a wide range of adjustability, the selection of a suitable articulator is a challenge for the dental practitioner. It is majorly based on treatment needs of the patient, chosen occlusion philosophy, and required degree of accuracy.[7] In addition, articulator classification systems also facilitate articulator selection and are imperative to using and teaching the theory and practice of articulation.

Several articulator classifications have been proposed since the early 20^th century taking into account the variety of articulators that have emerged during this period.[8,9,10,11,12,13,14,15,16,17] However, a majority of these classifications are confusing for the learners as they are not relevant to the present-day articulators. Among these, the International Prosthodontic Workshop 1972 classification[15] and the one proposed by Rihani in 1980[17] are commonly used and accepted. These classifications have included the acceptability of facebow transfer in the nonadjustable articulator category. We have a differing opinion here, any articulator that accepts facebow transfer supposedly cannot be nonadjustable. In addition, the University of Michigan classification is very comprehensive and difficult to visualize by young learners. This classification has a lot of parameters and does not include virtual articulators. Furthermore, with the advent and usage of virtual facebows and articulators in the ever-expanding world of digital dental practice,[18] it is a good time to propose a new classification that includes both mechanical and virtual articulators.

The purpose of this communication is therefore to provide a simpler and all-inclusive new articulator classification that aligns with current dental practice and progresses from conventional mechanical articulators to digital virtual articulators.

NEWLY PROPOSED ARTICULATOR CLASSIFICATION

The classification that we propose (MGT Classification)* is broadly adapted from the University of Michigan[16] and Rihani’s[17] classification; based on the adjustment capabilities of an articulator (facebow transfer, intercondylar distance adjustment) and its ability to accept records obtained from a patient (centric record, protrusive record, and lateral record), along with the inclusion of virtual articulators.

Category I: Mechanical articulators

Class 1: Nonsimulated articulators-accept only centric record.

Examples: Denar Automark, Barn Door.

Class 2: Partially simulated articulators – This class has been subdivided into 2a, 2b, and 2c, based on the adjustment capabilities of an articulator to accept facebow transfer, and its ability to accept records obtained from a patient-centric record, protrusive record, and lateral record.

Class 2a: Accepts facebow transfer and only centric record.

Example: Hanau Mate, Hanau Ulti-Mate, Denar Mark 310, Bio-Art A7 Fix.

Class 2b: Accepts facebow transfer, centric record and protrusive records.

Example: Whip Mix 2240, Denar Mark 320, Hanau H2, Bio-Art A7 Plus.

Class 2c: Accepts facebow transfer, centric record, protrusive record, and lateral records.

Examples: Whip Mix 2340, Whip Mix 4000 series, Whip MixModel 8500, Denar Mark 330, Hanau Wide-Vue series, Artex CR, SAM 3.

Class 3: Fully simulated articulators – Accepts facebow transfer, centric record, protrusive record, and lateral records. It has a provision of adjustable intercondylar distance.

Example: Denar 5A, Granger Gnatholator.

Category II: Virtual articulators

Class 1: Partially simulated virtual articulators do not record or reproduce individualized mandibular movement paths of each patient. Mathematically simulated articulators that use an average value for adjustment of additional articulator settings to reproduce mandibular movements.

Example: Ceramill-Artex, Ivoclar-Stratos 300.

Class 2: Fully simulated virtual articulators record and replicate exact mandibular movement paths using a specific digital tool, the jaw motion analyzer.

Examples: DentCam system, Kordass, and Gartner virtual articulator.

SUMMARY

A simple all-inclusive classification that is easy for the learners to comprehend has been proposed. This newly proposed classification system includes both mechanical and virtual articulators [Table 1] to match with the contemporary theory and practice. Although articulators have additional adjustable features such as reproducing immediate mandibular lateral translation and provision for Fischer’s angle and pantographic tracing, these have not been considered in the present classification. However, articulators that accept and can be adjusted to all of the above mentioned records will be classified as fully simulated.

Table 1.

MGT classification

Category I: Mechanical articulators
Class 1: Nonsimulated/fixed articulators	Class 2: Partially simulated articulators	Class 3: Fully simulated articulators
Can accept only	It is subdivided into three classes	Can accept all the five records
Centric record	Class 2a	Face-bow transfer
Example: Denar Automark, Barn Door	Accepts	Centric record
	Face-bow transfer	Protrusive records
	Centric record	Lateral records
	Example: Hanau Mate, Hanau Ulti-Mate, Denar	Intercondylar distance
	Mark 310, Bio-Art A7 Fix
	Class 2b         Accepts	Example: Denar 5A, Granger Gnatholator
	Facebow transfer
	Centric record
	Protrusive records
	Example: Whip Mix 2240, Denar Mark 320,
	Hanau H2, Bio-Art A7 Plus
	Class 2c
	Accepts
	Facebow transfer
	Centric record
	Protrusive records
	Lateral records
	Examples: Whip Mix 2340, Whip Mix 4000 series, Whip Mix Model 8500, Denar Mark 330,
	Hanau Wide-Vue series, Artex CR, SAM 3
Category II: Virtual articulators
Class 1: Mathematically simulated virtual articulators		Class 2: Fully simulated virtual articulators
Mathematically simulated articulators that use an average value for adjustment of additional articulator settings to reproduce mandibular movements		Example: Ceramill-Artex, Ivoclar-Stratos 300
It records and replicates exact mandibular movement paths using a specific digital tool, the jaw motion analyzer		Example: DentCam system, Kordass, and Gartner virtual articulator

Color coding: Color depicting the type of record accepted by the articulator: : Centric record : Face-bow transfer : Protrusive record : Lateral record : Intercondylar distance

Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.